This artist's drawing provided by Christo shows an image of a proposed art project by artists Christo that would suspend 5.9 miles of silvery, translucent fabric above parts of the Arkansas River in southern Colorado.

Christo updated the Denver Post on the progress of his planned Arkansas River installation called Over The River in an interview Thursday afternoon, October 17, 2013.

Opponents of artist Christo’s 19-year-old plan to drape the Arkansas River with fabric say they are girding for more battles even after a recent court decision upholding the Bureau of Land Management’s approval of the project.

“It’s too destructive to the people, to the environment and to the wildlife in Bighorn Sheep Canyon,” said Joan Anzelmo, spokeswoman for Rags Over the Arkansas River, or ROAR, an opposition group. “We have a lot of fight left in us, and we will exploit everything we can to prevent this project from happening.”

Christo and wife Jeanne-Claude, who died in 2009, searched hundreds of stretches of rivers in the West before proposing in 1996 to hang fabric curtains over miles of the Arkansas River.

The “Over the River” project entails draping polypropylene panels on bolt-anchored steel cables over 5.9 miles of a 42-mile stretch of federal land along the Arkansas River between Salida and Cañon City. The project would take 27 months to erect and would be on display for a mere two weeks before a three-month removal process.

ROAR’s federal lawsuit, brought by former University of Denver law professor Michael Harris and his environmental law students, argued the BLM had failed to follow federal environmental policy when it reviewed the project’s impacts to bighorn sheep and traffic on U.S. 50 through the canyon. Martinez rejected ROAR’s contention that the BLM’s 1,700-page environmental review of the project was “arbitrary and capricious.”

“The petitioner has noted various environmental effects that the project will have on federal lands in the United States, but its argument essentially boils down to a disagreement with the BLM’s approval of the project,” Martinez wrote in his 30-page decision. “Such disagreement is not sufficient to warrant reversal.”

It was the third ROAR legal challenge that failed to stop the project.

The Interior Board of Land Appeals in 2013 rejected ROAR’s argument that the BLM failed to properly scrutinize the project. A lawsuit filed in state district court challenging the Colorado State Parks — now Colorado Parks and Wildlife — decision to allow “Over the River” was dismissed in 2013.

The group, made up largely of residents in and around Bighorn Sheep Canyon, appealed the state court’s decision to the Colorado Court of Appeals. That decision is pending.

Anzelmo said the group is considering an appeal of Martinez’s ruling and noted that Harris, who has moved to another job, has agreed to continue representing ROAR.

Beyond legal challenges, the group is promising a public-relations blitz to expose the impacts of the project, Anzelmo said.

They will note how winds tore down the curtain Christo draped across the Rifle Gap in 1972 and how a woman was killed when winds hurled one of the 1,760 umbrellas he unfurled in the mountains north of Los Angeles in 1991, Anzelmo said.

“We want to expose the dangerous and destructive nature of this project,” she said.

A statement from Christo’s team this week said the recent ruling “makes a strong statement about why all prior challenges to the federal permit have now been rejected.”

Any appeal of the ruling, the team wrote, “would be nothing more than another attempt to delay the installation of ‘Over the River.’ ”

Christo isn’t announcing any dates for when “Over the River” will be ready for its late summer debut. His team is working to secure final permits and preparing for the installation. He’s also waiting for that Colorado Court of Appeals decision.

Christo estimates project costs, including the several years of federal review, at about $50 million. That’s all his cash, earned from selling sketches of his installations around the world.

At every step of the contentious “Over the River” project thus far, the indefatigable 79-year-old has said he embraces the criticism. Lawsuits and delays are part of the process. He and his wife of 51 years spent 26 years fighting to erect 7,503 fabric gates in New York City’s Central Park in 2005. It took 32 years to win approval to wrap 178 trees in a Swiss park in 1998.

At local meetings in Bighorn Sheep Canyon in 2012, the Bulgarian-born artist sat nodding and smiling as residents blasted not just his project, but his art. The heated discussions, the angst and the opposition are all part of the art, he said.

“For many years, all the people are thinking how the work will be beautiful, how the work will be awful,” Christo said in a 2013 interview with The Denver Post. “Basically the work is working in the mind of the people before it physically exists. This is probably the biggest satisfaction we have.”

Thunderstorms that originated in eastern Utah and along the Western Slope formed a squall line that produced damaging winds and power outages across the state Saturday afternoon, according to National Weather Service meteorologist Greg Hanson.